adding an map builder used in autogenerated JAX-RS endpoints

rest-adapter/src/main/java/uk/gov/justice/services/adapter/rest/builder/UnmodifiableMapBuilder.java

@@ -0,0 +1,31 @@
+package uk.gov.justice.services.adapter.rest.builder;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Builder class that builds an immutable map
+ *
+ */
+public class UnmodifiableMapBuilder<K, T> {
+    private final Map<K, T> map = new HashMap<>();
+
+    /**
+     * @param key
+     * @param value
+     * @return - builder instance with key and value set
+     */
+    public UnmodifiableMapBuilder<K, T> with(final K key, final T value) {
+        map.put(key, value);
+        return this;
+    }
+
+    /**
+     * @return an immutable map with entries set by invocations of the with
+     *         method
+     */
+    public Map<K, T> build() {
+        return Collections.unmodifiableMap(map);
+    }
+}

rest-adapter/src/main/resources/META-INF/beans.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<beans>
+
+</beans>

rest-adapter/src/test/java/uk/gov/justice/services/adapter/rest/builder/UnmodifiableMapBuilderTest.java

@@ -0,0 +1,42 @@
+package uk.gov.justice.services.adapter.rest.builder;
+
+import static org.hamcrest.collection.IsIterableWithSize.iterableWithSize;
+import static org.hamcrest.collection.IsMapContaining.hasEntry;
+import static org.junit.Assert.assertThat;
+
+import java.util.Map;
+
+import org.junit.Test;
+
+public class UnmodifiableMapBuilderTest {
+
+    @Test
+    public void shouldBuildEmptyMap() {
+        Map<String, String> map = new UnmodifiableMapBuilder<String, String>().build();
+        assertThat(map.entrySet(), iterableWithSize(0));
+    }
+
+    @Test
+    public void shouldBuildMapWithOneEntry() {
+        Map<String, String> map = new UnmodifiableMapBuilder<String, String>().with("key123", "valueABC").build();
+        assertThat(map.entrySet(), iterableWithSize(1));
+        assertThat(map, hasEntry("key123", "valueABC"));
+    }
+
+    @Test
+    public void shouldBuildMapWithThreeEntry() {
+        Map<String, String> map = new UnmodifiableMapBuilder<String, String>().with("keyA", "v1").with("keyB", "v2")
+                .with("keyC", "v3").build();
+        assertThat(map.entrySet(), iterableWithSize(3));
+        assertThat(map, hasEntry("keyA", "v1"));
+        assertThat(map, hasEntry("keyB", "v2"));
+        assertThat(map, hasEntry("keyC", "v3"));
+    }
+
+    @Test(expected=UnsupportedOperationException.class)
+    public void shouldThrowExceptionOnModificationAttempt() {
+        Map<String, String> map = new UnmodifiableMapBuilder<String, String>().build();
+        map.put("k1", "v1");
+    }
+
+}